ZACATON AS A PAPER-MAKING MATERIAL. 



21 



experimentally on a small scale, and doubtless in many cases this 

 attitude is justified. Experimentation on a small scale lias its own 

 valuable sphere of usefulness, but great care should be exercised in 

 its commercial interpretation. Therefore, with a view to giving this 

 material a more reliable or commercial paper value the work was 

 continued on a larger scale, more nearly under mill conditions and 

 at a place where the services of actual mill emploj^ees could be 

 secured for the work. 



The digester employed for this work was of the upright stationary 

 type, measuring about 2 feet in diameter by 10 feet high and heated 

 by direct steam. The cooked charge was ^' blown" in the regular 

 manner into a blow pit of ordinary construction, where it was drained 

 and washed free from black liquor. After screening in the regular 

 manner the stock was bleached with mill bleach liquor in a beating 

 engine and bleach chest, washed free from bleach residues, made into 

 the desired furnish, and suitably beaten, after which it was run 

 through a Jordan refiner and then to a Fourdrinier paper machine. 

 The greater part of this whole work was performed by the regular 

 miU employees.^ 



The material used for the four cooks of this test was dry, but had 

 previously molded to some extent, being the same as that used in 

 cooks Nos. 4, 5, and 6. Table V shows the cooking conditions and 

 the yields of the four cooks. 



Table V. — Conditions of cooking and total yields of fiber of four coohs of zacaton grass. 



Cook. - 



Charge, 

 bone dry. 



Caustic 



soda 



added. 



Concen- 

 tration of 

 caustic 

 soda. 



Cooking 

 pressure. 



-rT„,,„<, Yield, 

 pressure. "I^^J"' 



No. 7 



Pounds. 

 175 



182 

 192 

 186 



Per cent. 

 20 

 19 

 18 

 16 



41 

 90 



Pounds. 



100 



90 



90 



90 



5 38.6 



No. 8 



6 33.4 



No. 9 « 



5 44.6 



No. 10 a 





6 45.2 









a The charge in the digester was covered with water and heated to a steam pressure of 50 pounds per 

 square inch for 1 hour, after which the water extract was all arained off and the residue cooked in the regu- 

 lar manner. 



The higher yield of total fiber in cooks Nos. 9 and 10 is due to the 

 lower percentage of soda added and the fact that its concentration was 

 lowered by the water remaining in the grass after extraction. The 

 general appearance of the pulp of these four cooks was very similar; 

 they were soft feeling, bulky, and had a very silky luster. Screening 

 was done on a No. 10 cut screen, and in place of a pulp thickener the 

 screened stock was run over the wet end of a Fourdrinier paper 

 machine and taken off at the first press. This procedure left the 

 stock in fine condition to be transferred to the bleach beater. 



Much assistance and information was furnished by S. D. Warren & Co., Cumberland Mills, Me. 



